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Analysis of Internal Loss in Edge-Emitting Transistor Lasers
Date Issued
2014
Date
2014
Author(s)
Huang, Yu-Hao
Abstract
This thesis presents the fabrication and characterization of edge-emitting transistor lasers (EETLs). We measure the electrical and optical signal of the devices under room temperature (Kelvin Temp. 298 K) and low temperature (Kelvin Temp. 82 K). The structures of the devices in the experiment employ GaAs as the base material, and incorporate In0.2Ga0.8As quantum well as the active region for radiative recombination. After we finish device process, we coat dielectric mirrors on the cleaved laser facets with different coating conditions: the first type of device with one side high-reflection and the other side anti-reflection; the second one with both sides anti-reflection; the third one with both sides uncoated.
The measurement at room temperature shows that all devices with different coating conditions have the current gain larger than 1 when they operate at high base current and collector-to-emitter voltage. With different coating conditions, the devices show great differences on electrical and optical signals due to different Franz-Keldysh photon absorption effects happening at base-to-collector junction, varied by different photon confinement in the laser cavity. In addition, the optical spectrum will change because of the different coating conditions on each device.
The measurement at low temperature shows that not only the threshold carrier concentration will decrease but also internal loss, so the devices can operate under stimulated emission. We also compare the base recombination lifetime between different devices and conditions. We observe that the device with high-reflection coating on the two cavity facets has faster base recombination lifetime than the device without coating.
Finally, we analyze the internal loss of edge-emitting transistor lasers and define a new parameter called "effective internal loss" for transistor lasers. The effective internal loss considers the conventional losses in a light-emitter as well as the unique Franz-Keldysh absorption, which is a function of bias and photon energy. We list all calculated parameters of the transistor lasers in the end for future design of better performance transistor lasers.
The measurement at room temperature shows that all devices with different coating conditions have the current gain larger than 1 when they operate at high base current and collector-to-emitter voltage. With different coating conditions, the devices show great differences on electrical and optical signals due to different Franz-Keldysh photon absorption effects happening at base-to-collector junction, varied by different photon confinement in the laser cavity. In addition, the optical spectrum will change because of the different coating conditions on each device.
The measurement at low temperature shows that not only the threshold carrier concentration will decrease but also internal loss, so the devices can operate under stimulated emission. We also compare the base recombination lifetime between different devices and conditions. We observe that the device with high-reflection coating on the two cavity facets has faster base recombination lifetime than the device without coating.
Finally, we analyze the internal loss of edge-emitting transistor lasers and define a new parameter called "effective internal loss" for transistor lasers. The effective internal loss considers the conventional losses in a light-emitter as well as the unique Franz-Keldysh absorption, which is a function of bias and photon energy. We list all calculated parameters of the transistor lasers in the end for future design of better performance transistor lasers.
Subjects
電晶體雷射
法蘭茲-凱爾迪西光子吸收效應
鍍膜
內部損耗
Type
thesis
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Name
ntu-103-R01941063-1.pdf
Size
23.32 KB
Format
Adobe PDF
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